Apparatus and process for transferring a fiber web

ABSTRACT

Apparatus and process for separating a web of fibers from a doffer in a carding machine whenever a roller comb is provided adjacent to the peripheral surface of a doffer, said roller comb being wound on its circumference with a metallic wire in the form of tooth defined by an outwardly projecting portion forming a roundish curve. The roller comb is rotated in the same direction as that of the doffer at a lower rate of surface speed than that of the doffer. A web roller having a smooth surface is located adjacent to both said doffer and said roller comb below a straight line connecting the center of the doffer and the axis of the roller comb. The web roller is rotated in the direction opposite to that of the doffer at a lower rate of surface speed than that of said roller comb thereby forming a space in the form of triangle by said three means of the doffer, the roller comb and the web roller comb.

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INVENTOR BYwl pululwi ATTORNEYS APPARATUS AND PROCESS FOR TRANSFERRING A FIBER WEB This application is a continuation of application Ser. No. 755,182 filed Aug. 26, 1968, now abandoned.

This invention relates to metallic wire for roller comb of novel construction, which can peel the fibrous web off from the doffer of carding engine without any trouble. Furthermore the invention relates to a process and apparatus for collecting fibrous web from the doffer during carding operation, without any trouble even when the doffer is rotating at a high speed.

As well known, in a carding machine conventionally employed in the field of spinning industry, the lap fed through feel rolls is transferred to the carding cylinder with its top covered with a flat, by a taker-in mounted with metallic wire. The lap carded in the cylinder is fur-v ther transferred to a doffer mounted with metallic wire in the form of fibrous web, and peeled off therefrom by means of a doffer comb (or a fly. comb) vibrating at a rate of approximately 1,500 times per minute. Finally the web is collected through the funnel hole in the form of sliver. In this system of employing conventional fly comb, the recovery rate of the fibrous web from the doffer is limited. Therefore it has been proposed to perform the separation of fibrous web from the doffer with a roller comb wound with metallic wire. However, none of the heretofore proposed roller combs are perfectly free from the problems in the peeling action of fibrous web from the doffer comb, or in the separation and collection of web from the roller comb. Thus, with those roller combs, entanglement of the fibrous web with the doffer or roller comb, or formation of uneven web frequently take place.

Furthermore, it has been an accepted concept on known metallic wire that in order to assure the transfer of fibers with the sawtooth portion 'of the wire, the working angle of each tooth must be acute.

We now discovered, however, that the foregoing drawbacks in known roller combs can be effectively prevented, if a metallic wire with saw teeth of a configuration defined by a smoothly projecting curve, the two tangents at the two ends of the curve forming the angles of, respectively, 90 150 and 30 90 to the horizontal line extending'in the longitudinal direction of the metallic wire, is used as the metallic wire for the roller comb.

Accordingly, the object of the invention is to provide a novel metallic wire for roller comb with which the separation of fibrous web from the doffer as well as from the roller comb can be easily performed.

Another'object of the invention is to provide a process for collecting fibrous web from the doffer, with which it is possible to easily separate and collect fibrous web from the doffer without any trouble, even when the doffer is rotating at a high speed, in the carding operation of cotton orartificial staple fiber.

A still further object of the invention is to provide a carding machinewith which the carded sliver can be prepared at higher efficiencies than those possible with conventional carding machines.

According to the invention, metallic wire to be mounted on a roller comb for separating fibrous web from a doffer, which consists of an upper working section with saw teeth on the top and a base, the height and pitch of the saw teeth being, respectively, 1 10 mm and 2 30 teeth per lines meeting and each tooth being of a configuration defined by a smoothly projecting curve which tangentially contacts with two straight lineslmeeting the horizontal line extending in the longitudinal direction of the metallic wire, at the angles of, respectively, 150 and 30 90.

For a still better understanding of the invention, further'explanation will be given with reference to the attached drawings.

FIGS. l-A, 1'-B and l-C are respectively a side view, sectional view and a partially enlarged side view of the metallic wire of this invention, which are for explaining the dimensions and shapes of the each part of the metallic wire:

FIGS. 2-A and 2-3 are respectively a side view and sectional view showing the construction of conventional metallic wire:

FIGS. 3-A and 3-B are respectively a side view and sectional view showing the construction of a metallic wire with the saw teeth of the configuration outside the scope of the invention, i.e. saw teeth with pointed vertex, given for the purpose of comparison:

FIGS. 4-A and 4-B are respectively a side view and sectional view of one embodiment of the metallic wire of this invention:

FIGS. S-A and 5-B are respectively a side view and sectional view of another embodiment of the metallic wire of this invention:

FIGS. 6-A and 6-H are respectively a side view and sectional view of still another embodiment of the metallic wire of this invention:

FIG. 7 is a sectional view showing the arrangement of essential parts of a carding machine'useful for practicing the process of this invention: and

FIGS. S-A and. 88 illustrate the action of the web roller under operation of the calendering machine.

Hereinafter the terms denoting the dimensions and numerical values of the parts are used in the present specification and claims with the signifiance as defined with reference to FIGS. l-A, l-B and l-C as follows:

Total height Tooth height Base thickness Tip thickness Medium thickness Tooth pitch Minimum working angle Maximum back angle The metallic wire of the invention consists of base (1) and upper working section (2) with a large number of teeth (3) provided on the top thereof, as illustrated in FIGS. l-A, l-B and l-C. Each tooth has a configuration defined by asmoothly projecting curve (3) which tangentially contacts with the first line (a) inclined from the horizontal line (c) extending in the longitudinal direction of'the metallic wire with an angle (a) of 90 150, preferably 1 l0 and also with the second line (b) which is inclined to the said horizontal line (c) with an angle (B) of 30 90, preferably 50 70C. In the drawings, the curve is a tangential combination of an arc of circle having a radius R with two arcs of circles of radii, respectively, R and R The teeth of the above-described configuration are dis- In the metallic wire of the invention, the smoothly projecting curve 3 which defines the tooth configuration can be of any optional curved line, so far as the gradient of the tangent gradually decreases from one end of the tooth root to the tooth top, and gradually increases from the tooth top to the other end of the tooth root. The curve may be, for example, a part of a quadratic curve of a parabola, ellipse or circle, or may be a cycloid. Also thecurve may be composed of feet of two straight lines and a quadratic curve as abovedescribed which is tangentially continuous to those vertical feet;

Referring to FIGS. l-Aand l-C, the curve 3 can be further defined, besides by the already mentioned factors such as the angles a and [3 of the two tangents (a) and (b), pitch (P) of the teeth and tooth height (A), by

R, R, R

0.1 350 mm at least at least preferably 0.1 170 mm 0.4 mm 0.4 mm

When the radii of curvatures R and R are identical with the radius of curvature R,, the curve (3) becomes a part of circumference; and when R, and R are infinite, the curve (3) is a part of a quadratic curve which is tangentially continuous to two straight lines.

An important characteristic feature of the metallic wire of this invention is that the minimum working angle of each tooth isat least 90, and each tooth has a configuration defined by a smoothly projecting curve,- that is, the configuration having a curvature at its ver- ICX.

The metallic wires conventionally used in carding machines normally possess, as illustrated in FIGS. 2-A and 2-8, saw tooth (2) having an acute working angle a. When such metallic wire is mounted on the roller comb, the separation of fibrous web from the doffer is rather easy, but the separation and collection'of the web from the roller comb is difficult. On the other hand, if theworkinga of the tooth'is made obtuse as illustrated in FIGS. 3-A and 3-8, in orderto facilitate the separation of fibrous web on the metallic wire of roller romb, the performance is unsatisfactory for any practical purpose. To wit, with such metallic wire, separation failures of the web from the doffer frequently take place.

Surprisingly,'it is now discovered that metallic wire with saw teeth having a minimum working angle a of at least 90 and a configuration definedby a smoothly projecting curve, viz., a configuration having a curvature at the vertex, exhibits quite satisfactory performance. That is, the teeth action on the fibrous web on the doffer is quite sufficient for smooth transfer of the web from the doffer to the roller comb, and also the separation of web from the roller comb is facilitated.

In the metallic wire of this invention, the radius of curvature R, at the vertex of the tooth is closely correlated with the action of the wire to separatev the web from the doffer. Regardless the type of fibers used, larger R, is preferred for easier separation of fibrous web from the doffer, the particularly preferred range of R, being 1 4 mm.

The radius of curvature R at the root portion of the tooth is correlated with the action of the wire to sepa rate the fibrous web from the roller comb. When R is infinite, i.e., when the lower portion of the curve (3) is a straight line, in certain cases separation failure may occur with the frequency in the order of once per 1,000 lbs of treated fibers, depending on the type of fibers treated. For this reason, the radii of curvatures R and R at the root portions of the tooth are preferably within the range of 1 100 mm.

lnthe metallic wire of the invention, any two adjacent teeth are preferably continuous through a valley or trough (4) indicated by radius of curvature R, in FIG. l-C. Preferably the radius of curvature R of the trough (4), which is present between curves 3 and 3,

' is within the range of 0.1 20 mm, particularly 0.15

Operable dimensions and preferred dimensions of the other parts of the metallic wire of this invention are as follows:

Operable Preferred dimensions dimensions Total height 2 15 mm 2.5 7 mm Base thickness I 0.5 10 mm 1 5 mm Tip thickness 0.15 0.5 mm 0.2 0.3 mm Medium thickness 0.25 0.7 mm 0.3 0.5 mm

defined by the curve formed of an arc of a circle tan-- gentially combined with two straight lines of respectively the angle a and angle B. It should be obvious to the experts that the straight lines can be replaced by arcs of circles of larger radii of curvatures than that of the arc forming the vertex;

In FIGS. 5-A and 5-8, the tooth has a configuration defined by a parabola 3 tangentially contacting with two straight lines of respectively the angle a and angle B(a+fi=l).

In FIGS. 6-A and 6-B, the tooth has a configuration defined by a semi-circle tangentially contacting with two straight lines of respectively the angle a and angle [3 (a +5 The steel material of-the metallic wire is not critical,

but any steel which has been used for known metallic wires can be used. It is of course possible and preferred to impart higher degree of hardness to the upper working section, particularly the vertex portion, by the means known.

The mounting of the metallic wire onto the cylinder of roller comb of a carding machine can be effected in the conventional manner well known to the experts.

The metallic wire under a suitable tension is wound onto the predetermined position on the surface of the cylinder of roller comb, with pressing. After the mounting, the surfaces of the metallic wire may be ground, if desired.

The metallic wire thus wound onto the cylinder surface of roller comb normally provides 1,500 teeth, preferably 500 teeth, per square inch.

Furthermore, the invention provides a process for collecting the fibrous web in carding procedure, which comprises transferring the fibrous web on a doffer onto a roller comb by rotating the roller comb at a position close to the circumference of a rotating doffer which is mounted with the fibrous web, at a rate less than the surface speed of the doffer and inthe same rotating direction with the doffer; and simultaneously withdrawing the fibrous web from roller comb by rotating a smooth-surfaced webrollerat a position on the side of the transfer of the fibrousweb from the doffer tothe roller comb,and close to the circumferences of the doffer. and roller comb, ata surface speed of 50 200 percent of that of the roller comb and in the direction opposite from that of the roller comb, characterized in that the said roller comb is wound with metallic wire which consists of an upper working section with saw teeth on the top and a base, the. height and'pitch of the saw teeth being, respectively, .1 10 mm and 2 teeth per inch,and each tooth being of a configuration defined by a smoothlyprojecting curve whichtangentially contacts with two straight lines meeting the horizontal line extending in the longitudinal direction of the metallic wire at the angles of, respectively, 90 150 and 30 90.

The above process of the invention can be easily practiced with a carding machine which comprises a doffer; a roller comb positionedat the opposite side from the cylinder with respect to the perendicular line from the center of the doffer, and atclosely adjacent the circumference of the doffer; a smooth-surfaced web roller positioned below an imaginary line linking the shaft of the roller comb and the center of the doffer, and at closely to the circumferences of the roller comb and doffer; and .a means for collecting and withdrawing the fibrous web from the roller comb, characterized in that the roller comb is mounted, by winding, with a metallic wire which consists of an upper working section with saw teeth on the top and a base, the height and pitch of the saw teeth being, respec tively, 1 10 mm and 2 30 teeth per inch, and each tooth being of a configuration defined by a smoothly projecting curve which tangentially contacts with two I straight lines meeting the horizontal line extending in longitudinaLdirection of the metallic wire, at the angles of, respectively, 90 150 and 30 90.

The essential parts of an apparatus suited for practicing the process of this invention are shown by crosssection in FIG. 7 of the attached drawings. Referring to FIG. 7, a fibrous lap:is wound back by a pair. of feed rolls and supplied to the tip of a dish plate, to be combed with the saw teeth of a taker-in wound with metallic wire. The fibers are transferred to the saw teeth of a carding cylinder (partially shown as 10) in the form of web, and carded'between the saw teeth of the flats and those of the carding cylinder. Thus carded fibers onthe saw teeth (11) of carding cylinder (10) are transferred onto the saw teeth (21) of the doffer (20) which is rotating in a direction opposite from that of the cylinder, in the form of fibrous web. Above dish plate, taker-in, carding cylinder, doffer, and their arrangement are themselves well known as the parts and mechanism of conventional carding machine.

In accordance with the invention, a roller comb (30) wound with the above-specified metallic wire (31) is disposed at the opposite side from the cylinder with respect to a perpendicular line passing through the driving shaft (22) of thedoffer (20), and at a close position to the circumference of the same dofferfThe roller comb (30) is rotated in the same direction with that of the doffer (20), from the power sourceof the carding machine through adriving mechanism such aschain, belt or gear (not shown), by means ofa driving shaft (32). According to the invention, the surface speed of the roller comb is less than that of the doffer. Preferably the surface speed of the roller-comb is 95 percent, preferably, percent, of the surface speed of doffer. The ratio of diameters between the doffer and roller comb preferably ranges l/l0 1/2, particularly l/4 1/6.

In the conventional process of separating the fibrous web on the dofferby means of a vertical vibrating fly comb, the rotation speed of the doffer is under a strict restriction. Consequently the increase of production rate of the carded sliver is also impossible beyond certain limit. Whereas, according to the subject invention, the separation of the fibrous webs on'the roller comb, is easily performable under the surface speed of the doffer varying over a wide range of 300 20,000 inches/min, using the roller comb mounted with the specified novel metallic wire. Again, with the conventional carding machines equipped with roller combs, it has been an accepted practice to operate the roller comb at a surface speed greater than that of the doffer. Conventionally the webs held on a doffer of low rotation speed are separated from the doffer by a roller comb rotating at agreater surface speed than that of the doffer. As the result, however, the web held onthe conventional rollercomb has a thickness less than that of the web on the doffer, and is separated from the roller comb with considerable difficulty. Furthermore, in the conventional carding system employing roller comb, the surface speeds of the doffer and cylinder are restricted by that of the roller comb, and consequently it is impossible to increase the operation speed of the carding machine as a whole to improve the production rate of cardedsliver beyond a certain level.

Whereas, in accordance with the invention, both the transfer of fibrous web from the doffer to the roller comb and the separation of web from the roller comb are remarkably facilitated, by the use of the roller comb mounted with the metallic wire having the abovespecified upwardly curved saw teeth, and also by making the surface speed of the roller comb less than that of the doffer. That is,'according to the mechanism as employed in this invention, the thickness of the fibrous web on the roller comb increases in comparison with that of the web on the doffer, in inverse proportion to the surface speed ratio between the two. Consequently the mutual entanglement (friction) of the fibers increases, and thick web layer on the roller comb exerts sufficient force on the thin and hard separable web layer on the doffer to assist easy separation of the latter. Also the separation of web from the roller comb is facilitated by the above-described action as well as centrifugal force of the roller comb. (The specified configuration of the saw tooth of the metallic wire remarkably enhances the action of centrifugal force.) b

Further in accordance with the invention, a web roller (40) is disposed below the imaginary line linking the center of doffer (20) and shaft of roller comb (30), i.e., in the rotating direction of the roller comb with respect to the said line, and at a position-close to the circumferences of the roller comb and doffer.

The web roller (40) has asmooth surface, and is rotated counter to the rotation of roller comb, from the power source of the carding machine, through a suitable drawing mechanism such as gear, chain or belt, by means of a driving shaft (41). The preferred surface speed of the web roller ranges 50 200 percent, particularly 80 l20.percent of the surface speed of the roller comb. The diameter ratio between the doffer and the web roller is preferably within the range of 1/30 1/6.

The provision of the web roller facilitates the withdrawal of fibrous web from the roller comb. The web (100) separated from the web roller and withdrawn therefrom is led to a web guide plate (50) with two side walls gradually approaching to each other toward one end, and compressed by a pair of calender rollers (61) and (62) into a sliver. The sliver is collected into a can through a coiler (not shown).

In the apparatus of the invention, the clearance between the roller comb and doffer is preferably in the order of 40/1000 inch, particularly /1000 15/1000 inch. Also the clearance between the roller comb and web roller, and that between the web roller and doffer, may be each within the range of 0 1 inch, particularly A; /2 inch.

Another advantage of the process and apparatus of the invention is that the operation of passing the web through the calender and the coiler head is extremely the space between the roller comb and web roller, as

illustrated in FIG. 8-B. Thus the initial drawing operation of fibrous web at the starting time of the carding operation can be easily performed.

Hereinafter the invention will be explained with reference to the following example.

Example The metallic wire as illustrated in FIGS. l-A, l-B and l-C of the dimensions below was mounted on a roller comb of 137 mm in diameter.

This roller comb and a web roller of 47 mm in diameter were mounted in a conventional carding machine having a doffer of 27 inches in diameter, at the relative positions as indicated in FIG. 7.

The surface speeds of the doffer, roller comb, and web roller, and the clearances therebetween were as follows:

Surface speed (inch/min.)

Doffer 4,2420 Roller comb 3,600 Web roller 2,340

Clearances (inch) Between doffer and roller comb 7/1,000 Between roller comb and web roller 9/32 Between web roller and doffer A raw cotton lap produced in USA. was supplied to the feed rolls of the carding machine in the purpose of manufacturing cotton yarn of 20 counts. During the processing of 1,000 lbs. of the lap, no separation failure of fibrous web took place either from the doffer or from the roller comb.

For the purpose of comparison, the similar carding was performed with the same carding machine except that the roller comb was mounted with the metallic wire having conventionally shaped saw teeth. The working angle (a) of the saw tooth was 79 and the back angle (B) was 101. As the result, while no trouble occurred in the separation of fibrous web from the doffer, separation'failures from the roller comb took place with the frequency of at least 30 times per 100 lbs. of the cotton lap processed.

Also when the configuration of the saw tooth on the metallic wire of roller comb was changed to that having a pointed vertex, the working angle (a) being 120 and back angle (B) being 60, the separation failure of fibrous web from the doffer took place at least 3 times per 100 lbs. of the lap, and that from the roller comb also occurred with the frequency of at least 2 times per 1,000 lbs. of the lap carded.

What is claimed is:

1. Apparatus for detaching from the doffer of a carding machine having a carding cylinder and collecting a web of fibers, said apparatus comprising a doffer; a roller comb covered with metallic wire having wire teeth defined by a smoothly outwardly projecting curve, lo cated on the side opposite said cylinder with respect to a perpendicular passing through the center of said doffer, disposed closely adjacent to the periphery of said doffer, said roller comb being rotatable at a lower speed than the surface speed of said doffer in the direction the same as the rotating direction of the doffer; a web roller having a smooth surface located below with respect to a line connecting the axis of said roller comb and the center of said doffer, disposed with its surface closely adjacent to the peripheries of said roller comb and said doffer, said web roller being rotatable in the direction opposite to that of said roller comb at a surface speed less than the surface speed of said roller comb; said doffer, said roller comb, and said web roller being arranged to define a generally triangular space in cross section for storing a web of fibers detached from said roller comb in a convoluted fashion; and a pair of calender rolls for collecting said web of fibers discharged outside through the nip of the roller comb and the web roller.

2. Apparatus according to claim 1 wherein a guide plate is disposed to lead to said calender rolls said web of fibers discharged outside through the nip of said roller comb and said web roller.

3. An apparatus for detaching a web of fibers from a carding machine having a carding cylinder, said apparatus comprising a rotating doffer; a roller comb covered with metallic wire having wire teeth defined by a smoothly outwardly projecting curve, said roller comb disposed closely adjacent to the periphery of said doffer on the side opposite said cylinder with respect to a perpendicular passing through the center of the doffer; means for rotating said roller comb in the direction the same as that of said doffer at a surface speed less than that of said doffer; a web roller having a smooth surface disposed with its periphery closely adjacent to the peripheries of said roller comb and said doffer, and located below a line connecting the axis of between said roller comb and said web roller. 

1. Apparatus for detaching from the doffer of a carding machine having a carding cylinder and collecting a web of fibers, said apparatus comprising a doffer; a roller comb covered with metallic wire having wire teeth defined by a smoothly outwardly projecting curve, located on the side opposite said cylinder with respect to a perpendicular passing through the center of said doffer, disposed closely adjacent to the periphery of said doffer, said roller comb being rotatable at a lower speed than the surface speed of said doffer in the direction the same as the rotating direction of the doffer; a web roller having a smooth surface located below with respect to a line cOnnecting the axis of said roller comb and the center of said doffer, disposed with its surface closely adjacent to the peripheries of said roller comb and said doffer, said web roller being rotatable in the direction opposite to that of said roller comb at a surface speed less than the surface speed of said roller comb; said doffer, said roller comb, and said web roller being arranged to define a generally triangular space in cross section for storing a web of fibers detached from said roller comb in a convoluted fashion; and a pair of calender rolls for collecting said web of fibers discharged outside through the nip of the roller comb and the web roller.
 2. Apparatus according to claim 1 wherein a guide plate is disposed to lead to said calender rolls said web of fibers discharged outside through the nip of said roller comb and said web roller.
 3. An apparatus for detaching a web of fibers from a carding machine having a carding cylinder, said apparatus comprising a rotating doffer; a roller comb covered with metallic wire having wire teeth defined by a smoothly outwardly projecting curve, said roller comb disposed closely adjacent to the periphery of said doffer on the side opposite said cylinder with respect to a perpendicular passing through the center of the doffer; means for rotating said roller comb in the direction the same as that of said doffer at a surface speed less than that of said doffer; a web roller having a smooth surface disposed with its periphery closely adjacent to the peripheries of said roller comb and said doffer, and located below a line connecting the axis of said roller comb and the center of said doffer; means for rotating said web roller in the direction opposite to that of said roller comb and at a surface speed less than the surface speed of said roller comb; the peripheries of said doffer, said roller comb and said web roller cooperating to form a generally triangular space in cross-section for causing a web of fibers initially detached from said doffer to be stored in a convoluted fashion in said space and then discharged in a single mass from between said roller comb and said web roller. 